chore(deps): bump diff in /actions/helm/generate-docs

Bumps [diff](https://github.com/kpdecker/jsdiff) from 5.2.0 to 5.2.2.
- [Changelog](https://github.com/kpdecker/jsdiff/blob/master/release-notes.md)
- [Commits](kpdecker/jsdiff@v5.2.0...v5.2.2)

---
updated-dependencies:
- dependency-name: diff
  dependency-version: 5.2.2
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]